We will examine genetic variation at the Pt-10, amylase and acid phosphatase-3 loci in Drosophila pseudoobscura and D. persimilis. Different alleles at these loci show associations with different third chromosome inversions. Structural variants at these loci will be distinguished by acrylamide gel electrophoresis of proteins and enzymes in gels of different concentrations, different pH's and by isoelectric focusing. Polymorphism due to different number of cysteine residues with free sulfhydryls will be studied by reacting these allozymes with thiol reagents and determining their electrophoretic mobility. Allelic variants will also be distinguished by heat and urea denaturation. We will purify amylase from different strains with varying activity levels and study the kinetics and thermolability of these amylase allozymes. Variation in the activity level of octanol dehydrogenase-1 will be studied by crossing various strains to a reference strain with different electrophoretic mobility allozyme and examining the staining intensity of bands on gels in extracts of F1 heterozygotes. We will also study the activity variation of the AP-3 allozymes similarly. Genetic analyses will be performed with any newly discoverd variants.